Sapling (5/6) #7
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Sapling (5/6) #7
I know how to solve for #7, but what I'm confused about is why are we subtracting the final mass from the initial mass instead of vice versa? Don't we usually do Tfinal - Tinitial to find the mass difference? What is it Tinitial - Tfinal for this question?
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Re: Sapling (5/6) #7
For this question you aren't necessarily trying to find the change in mass over time. The reason why you do initial mass (of the liquid) - final mass (of the liquid) is because that number will give you how much of your liquid has been vaporized. (If you had 100g of water in your cup and later you have 60g of water in your cup, then you know 40g of water vaporized).
After finding the amount of sample that has been vaporized, you can do (energy supplied/mol of sample vaporized) to find the molar enthalpy of vaporization.
After finding the amount of sample that has been vaporized, you can do (energy supplied/mol of sample vaporized) to find the molar enthalpy of vaporization.
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Re: Sapling (5/6) #7
In this case, you are looking for the numbers of moles consumed in order to find the Enthalpy of Vaporization.
You would subtract the final mass from the initial mass in order to get a positive value for grams consumed in the reaction.
Either way works though. As long as you know the number of moles consumed, the sign will be positive and not negative.
You would subtract the final mass from the initial mass in order to get a positive value for grams consumed in the reaction.
Either way works though. As long as you know the number of moles consumed, the sign will be positive and not negative.
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